udgrade_nest*


Routine to degrade or prograde the pixel size of a HEALPix map indexed with the NESTED scheme. The degradation/progradation is done assuming an intensive quantity (like temperature) that does NOT scale with surface area.
In case of degradation, a big pixel that contains one or several bad pixels will take the average of the valid small pixels, unless a 'pessimistic' behavior is assumed in which case the big pixel will take the bad pixel sentinel value. In case of progradation, a bad pixel only spawns bad pixels.
The routine accepts both mono and bi-dimensional maps.

Location in HEALPix directory tree: src/f90/mod/udgrade_nr.f90 


FORMAT

call udgrade_nest*( map_in, nside_in, map_out, nside_out[, fmissval, pessimistic] )

Arguments appearing in italic are optional.


ARGUMENTS

name & dimensionality kind in/out description
       
map_in(0:12*nside_in**2-1) SP/ DP IN mono-dimensional full sky map to be prograded or degraded.
map_in (0:12*nside_in**2-1,1:nd) SP/ DP IN bi-dimensional full sky map to be prograded or degraded. The routine finds the second dimension (nd) by itself.
nside_in I4B IN the ${N_{\rm side}}$ resolution parameter of the input map. Must be a power of 2.
map_out(0:12*nside_out**2-1) SP/ DP OUT mono-dimensional full sky map after degradation or progradation.
map_out (0:12*nside_out**2-1,1:nd) SP/ DP OUT bi-dimensional full sky map after degradation or progradation. The second dimension (nd) should match that of the input map.
nside_out I4B IN the ${N_{\rm side}}$ resolution parameter of the output map. Must be a power of 2. If nside_out > nside_in, the map is prograded (ie, more and smaller pixels) with each pixel having the same value as its parent; otherwise, the map in degraded (ie, fewer larger pixels), with each pixel being the average of its (nside_in/nside_out)2 components.
fmissval SP/ DP IN sentinel value given to bad pixels in input and output maps.default:\tt HPX_SBADVAL or \tt HPX_DBADVAL
pessimistic LGT IN if set to .true., during a degradation, a big pixel containing at least a small bad pixel will be returned as bad as well, instead of taking the average of the remaing valid pixels. default:.false.


EXAMPLE:

use udgrade_nr
call udgrade_nest(map_hi, 256, map_low, 64)
Degrades a NESTED ordered map with ${N_{\rm side}}=256$ into a NESTED map with ${N_{\rm side}}=64$


RELATED ROUTINES

This section lists the routines related to udgrade_nest*

udgrade_ring
prograde or degrade a RING ordered map.

Version 3.31, 2017-01-06